The End of Scars: Scientists Discovered How to Regenerate Human Skin

IN BRIEF

A team of scientists from the Perelman School of Medicine at the University of Pennsylvania found a way to get skin to regenerate using fat cells.

According to the researchers, the secret is to regenerate hair follicles first – the fat will regenerate in response to the signals from those follicles

AS IF IT NEVER HAPPENED

The human body can do many impressive things. Despite years of evolution honing its capability to carry out the complicated mechanisms needed to ensure our survival, the body has not refined the process of healing skin. Sure, wounds inflicted on the body’s largest organ can heal, but we are left with scar tissue.

A team of scientists from the Perelman School of Medicine at the University of Pennsylvania however, believe they have found a way to do the previously impossible – allow skin to regenerate using fat cells.

Image Credit: Penn Medicine

Adipocytes, the type of skin that regenerates after we get superficial cuts, is filled with fat cells that allow it to blend easily to the rest of your skin as it heals. Scar tissue (made up cells called myofibroblasts), which occurs as our skin heals from deep cuts, looks very different because it contains no fat cells or hair follicles.

“The findings show we have a window of opportunity after wounding to influence the tissue to regenerate rather than scar,” said the study’s lead author Maksim Plikus, PhD, an assistant professor of Developmental and Cell Biology at the University of California, Irvine.

George Cotsarelis, chair of the Department of Dermatology at the University of Pennsylvania, explains,”the secret is to regenerate hair follicles first. After that, the fat will regenerate in response to the signals from those follicles.”

WINDOW OF OPPORTUNITY

The scientists just had to figure out where the signals were coming from. They eventually identified a factor called Bone Morphogenetic Protein which instructs the myofibroblasts to become fat. “Typically, myofibroblasts were thought to be incapable of becoming a different type of cell,” Cotsarelis said. “But our work shows we have the ability to influence these cells, and that they can be efficiently and stably converted into adipocytes.”

While the discovery is indeed impressive, it should be noted that the experiment is still in its early stages and serves only to demonstrate proof of concept.

Currently the process has only been proven to work in mice and human skin samples. Achieving hair follicle growth in a wound attached to a living human might prove to be more difficult. But should science find a way to do this, we may not have to worry about wounds leaving scars ever again.

Outside of obvious applications to prevent scarring, adipocyte loss is also a known side-effect of other medical conditions, including HIV treatments. The aging process leads to natural loss of these cells as well, which causes permanent wrinkling of the skin. These findings could pave the way for a safer, and possibly permanent, way to address these cosmetic concerns.

I’m not sure if I find it more ironic or more serendipitous that I wrote this today at 2:15pm –

“I’m surprised that we haven’t heard more about this recently. There are articles going back to 2004 (like this one) showing the successful use of stem cells to generate hair. Five years later, it is still not available?”

Elaine Fuchs, head of the Laboratory of Mammalian Cell Biology and Development at Rockefeller University, is researching how stem cells in hair follicles are able to regenerate — research that may one day lead to the promised land of stem cell cloning techniques for hair loss. “Throughout our lifetime, each hair follicle undergoes cyclical bouts of growth, destruction and rest through an intrinsic stem cell population,” Dr. Fuchs told Science Daily recently. “It provides an excellent opportunity to investigate the molecular process of tissue regeneration and stem cell self-renewal.”

For a new round of hair growth to begin, stem cells in the hair follicle must receive a signal to divide. In response to this signal, the hair follicle regenerates first by growing downward through the skin’s middle layer, the dermis, and then producing the specialized cells that form the hair. After a period during which the hair grows longer, stem cells stop dividing, and the hair follicle gradually retracts again. There is then a period of rest and the cycle repeats.

Fuchs and her team have for several years been exploring the infrequently dividing stem cells located near the base of the hair follicle in a compartment known as the bulge. This time they focused on a much smaller cluster of often-ignored cells called the hair germ, located at the very bottom of this structure. Although little is known about the hair germ, scientists postulate that it emerges from the bulge at the end of the destructive phase of the hair cycle.

In their work, to be highlighted in the February 6 issue of Cell Stem Cell, Fuchs and her team scrutinized the hair cycle through the resting phase and discovered that during most of this time, both the bulge and the hair germ remain dormant. By isolating cells from both the hair germ and the bulge, they also confirmed that the two are molecularly very similar, suggesting that the germ does indeed originate from the bulge. The researchers believe, however, that toward the end of the resting phase, the hair germ gets activated to proliferate before the bulge. Moreover, the team showed that the activating signal comes from a structure known as the dermal papilla.

Stem Cells In Hair Follicles Point To General Model Of Organ Regeneration

ScienceDaily (Feb. 13, 2009) — Most people consider hair as a purely cosmetic part of their lives. To others, it may help uncover one of nature’s best-kept secrets: the body’s ability to regenerate organs. Now, new research from Rockefeller University gets to the root of the problem, revealing that a structure at the base of each strand of hair, the hair follicle, uses a two-step mechanism to activate its stem cells and order them to divide.

The mechanism provides insights into how repositories of stem cells may be organized in other body tissues for the purpose of supporting organ regeneration.

“The hair follicle is like a mini-dispensable organ,” says Elaine Fuchs, head of the Laboratory of Mammalian Cell Biology and Development. “Throughout our lifetime, each hair follicle undergoes cyclical bouts of growth, destruction and rest through an intrinsic stem cell population. It provides an excellent opportunity to investigate the molecular process of tissue regeneration and stem cell self-renewal.”

For a new round of hair growth to begin, stem cells in the hair follicle must receive a signal to divide. In response to this signal, the hair follicle regenerates first by growing downward through the skin’s middle layer, the dermis, and then producing the specialized cells that form the hair. After a period during which the hair grows longer, stem cells stop dividing, and the hair follicle gradually retracts again. There is then a period of rest and the cycle repeats.